Field of the Invention
This disclosure relates to an image forming apparatus configured to form an image on a sheet.
Description of the Related Art
Hitherto, an image forming apparatus such as a printer including a first discharge roller that discharges a sheet, to which toner is fixed, to a sheet discharge tray and a second discharge roller that is able to switchback the sheet, for example, for duplex printing on the sheet is known.
As an example of such an image forming apparatus, an image forming apparatus configured to allow a second discharge roller to be normally and reversely rotatable by a stepping motor has been proposed in JP-A-2003-215874. The image forming apparatus conveys the sheet by normally rotating the second discharge roller until a trailing edge of the sheet passes through a reverse sensor and then conveys the sheet to a duplex sheet re-feed path by reversely rotating the second discharge roller.
However, the image forming apparatus described in JP-A-2003-215874 needs to reverse a rotating direction of the stepping motor and accelerate the stepping motor after decelerates and stops the stepping motor when switching a rotating direction of the second discharge roller. Therefore, a downtime of the stepping motor becomes long and throughput is reduced when performing duplex printing.
In addition, it is considered that the stepping motor is configured to normally and reversely rotate a drive force transmitted to the second discharge roller by a gear train and the like while maintaining a state in which the stepping motor is rotated in one direction. However, even in such a configuration, when the rotating direction of the second discharge roller is switched by the gear train, a large load is applied in a direction in which the rotation of the stepping motor that is a drive source is hindered.
As a result, there is a problem that time for switching the rotating direction of the stepping motor becomes long and the throughput is reduced.